1. Field of the Invention
The present invention relates to a method of manufacturing a liquid jet head which ejects jet liquid and, more particularly, to a method of manufacturing an ink-jet recording head which ejects ink droplets from nozzle orifices by pressurizing ink supplied within pressure generating chambers communicating with the nozzle orifices for ejecting ink droplets, through piezoelectric elements or heater elements.
2. Description of the Related Art
In an ink-jet recording head, part of each pressure generating chamber, which communicates with each nozzle orifice for ejecting ink droplets, is composed of a vibration plate, and this vibration plate is deformed by piezoelectric elements to pressurize ink within the pressure generating chambers, and thus ink droplets are ejected from the nozzle orifices. For such an ink-jet recording head, the following two types of ink-jet recording heads have been put into practical use: one using a piezoelectric actuator of a longitudinal vibration mode, which extends and contracts in an axial direction of a piezoelectric element; and one using a piezoelectric actuator of a flexure vibration mode.
The former can change the volume of each pressure generating chamber by allowing an end face of the piezoelectric element to abut on the vibration plate and can be manufactured as a head suitable for high-density printing. However, a difficult process is required that the piezoelectric element is cut into a comb-teeth shape to make the piezoelectric element coincide with an array pitch of the nozzle orifices. Moreover, work of aligning the cut piezoelectric elements with the pressure generating chambers and fixing the piezoelectric elements thereto is required. Thus, there has been a problem that a manufacturing process thereof is complicated.
On the other hand, in the latter, the piezoelectric elements can be fabricated on the vibration plate by a relatively simple process of attaching a green sheet, that is a piezoelectric material, to the vibration plate in accordance with shapes of the pressure generating chambers and performing baking thereof. Nevertheless, a certain area is required because of the use of flexure vibration. Thus, there has been a problem that high-density arrangement is difficult.
Meanwhile, in order to resolve the disadvantage of the latter recording head, a proposal has been made in which a uniform piezoelectric material layer is formed over the entire surface of the vibration plate by use of a deposition technology, and then this piezoelectric material layer is cut into pieces having a shape corresponding to each of the pressure generating chambers by use of a lithography method, thus forming piezoelectric elements so as to be independent for the respective pressure generating chambers (for example, refer to Japanese Patent Laid-Open No. Hei 5 (1993)-286131).
Accordingly, work of attaching the piezoelectric elements to the vibration plate is no longer required, and the piezoelectric elements can be fabricated with high density by use of a precise and simple method such as the lithography method. In addition, there is an advantage that a thickness of each piezoelectric element can be reduced and thus high-speed drive becomes possible.
In the case of arranging the piezoelectric elements with high density as described above, it is required to ensure rigidity of compartment walls which define the pressure generating chambers, by forming a passage-forming substrate to be relatively thin. However, since the passage-forming substrate is formed using a silicon wafer with a size of, for example, about 6 to 12 inches in diameter, reducing the thickness of the silicon wafer easily causes cracks or the like. Therefore, there has been a problem that handling of the passage-forming substrate is difficult.
Moreover, there is another proposal regarding a method of forming a piezoelectric element and the like while rigidity of a passage-forming substrate is ensured by joining a sacrificial wafer to one surface of the passage-forming substrate (silicon wafer) (for example, refer to Japanese Patent Laid-Open No. 2003-133610). However, this manufacturing method using the sacrificial wafer has the following problems: the passage-forming substrate cannot be well positioned; positioning of the passage-forming substrate is time-consuming and, at the same time, a positioning process is required; and cracks occur in the periphery of the passage-forming substrate to which the sacrificial wafer is joined in the manufacturing process.
These problems can be seen not only in the case of the ink-jet recording head which ejects ink, but in a method of manufacturing another liquid jet head which ejects liquid other than ink, as a matter of course.